Frozen strain moiré used in the analysis of impact loading

This paper presents a solution to the problem of the displacement fields and strains in a semi-infinite plate with two half-circular holes during the propagation of a stress wave. The solution was realized experimentally by means of the method of the frozen strain moiré using a double-pulse ruby laser. The load of impact was applied by a pendulum hammer. Two suitable external-trigger mechanisms were used to fire the ruby laser at predetermined intervals. The moiré fringe patterns of the U and V displacement fields were recorded on a holographic film adhered to the specimen at different time delays after impact.